Cephalexin Safe in Pregnancy

Status

caution Last reviewed: 2026-05-16 · Confidence: moderate

Reason

Pregnancy data are limited, but official labeling does not show a clear drug-related risk. Use only if needed and reviewed by your prescriber.

Drug Information

Brand Name
Keflex
Generic Name
cephalexin
Drug Class
cephalosporin antibiotic
FDA Category
N/A (PLLR narrative label)
Rx Status
prescription

Safe Amount

Dosage must be determined by your provider based on individual risk/benefit.

Effects

Pregnancy
Official FDA labeling says use during pregnancy only if clearly needed; no pregnancy dose adjustment is listed.
Mother
May cause allergic reactions, stomach upset, diarrhea, or yeast infection. Tell your prescriber about penicillin or cephalosporin allergy.
Baby
No clear increase in major birth defects, miscarriage, or other fetal harm has been found in official labeling; data are limited.

Trimester Notes

1st Trimester
No known first-trimester-specific warning in official FDA labeling, but human data are limited.
2nd Trimester
No trimester-specific warning in official FDA labeling.
3rd Trimester
No trimester-specific warning in official FDA labeling; use only if needed and as prescribed.

Conditions & Warnings

  • Consult OB/GYN or prescriber
  • Prescription drug: review before starting, stopping, or continuing
  • Tell your prescriber if you have a penicillin or cephalosporin allergy

Alternatives

  • Discuss other pregnancy-appropriate antibiotics with your prescriber based on the infection and culture results

References

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